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Rak Mesba
Technology > Application > Megascale Engineering
Galactography > Systems and Worlds > Systems & Worlds Q - R
Sophonts > Xenosophonts
Galactography > Systems and Worlds > Systems & Worlds Q - R
Sophonts > Xenosophonts
A xenosophont megastructure in the form of a circumstellar disc | |
 Image from Steve Bowers | |
| Reflective statites above the poles of this star reflect light onto the surface of the disc, emulating a day length of 20.5 hrs. The inner and outer edges of this disk cannot support a biosphere, since gravity is not normal to the surface in these locations; instead these location hold power collection arrays and other infrastructure. | |
Rak Mesba - Data Panel | |
| Star | YTS 8222-0109319 |
|---|---|
| Right Ascension | 11h38m42.2437s |
| Declination | -63d32m00.0468s |
| Distance from Sol | 6317.7311 LY (1.9380 kpc) |
| Absolute Magnitude | 2.60 |
| Apparent magnitude | 14.03 |
| Luminosity | 7.82 x Sol |
| Class | F0 V |
| Surface temperature | 7200 K |
| Radius 1217100 km | (1.77 x Sol) |
| Rotation period | 22.2348 days |
RAK MESBA STRUCTURE | |
| Inner radius | 1.3314 AU |
|---|---|
| Outer radius | 1.9814 AU |
| Thickness | 184.0001 km |
| Mean density | 59048.8342 kg/m^3 |
| Total surface area | 2.6808 e+17 km^2 (5.2558e+8 x Earth) |
| Mass | 2.9127 e+33 kg (1464.4565 solar masses) |
| Surface gravity | 9.1125 meters/sec^2 (0.9292 g) |
| Mean atmospheric pressure | 200.5357 kPa (1.9786 atm) |
| Period of revolution | 222.3532 days |
"Rak Mesba" (meaning "giant washer" in the discoverer's native language, a dialect of neo-Malay) is a very large flattened disc-shaped habitat orbiting an otherwise unremarkable F0 V star in the constellation Centaurus (there are indications the star was artificially evolved to its current state, and that it may once have been a much more massive O-type star at some relatively recent time in its history). The object and its star, YTS 8222-0109319, are located just coreward of IC 2944 (the "Running Chicken Nebula"), and the dust of this nebula had obscured it to some extent. At first suspected to be a very cold and stable accretion disc, the artificial nature of the object was realised after a few decades of observations. At 6317 light years from Sol, there was no immediate prospect of sending a probe there, so it was relegated to an interesting object to be observed closely until technology and circumstance could make such a mission feasible.
The gradual expansion of the Terragen Sphere seemed likely to bring this object within reach, although this expansion was somewhat delayed by the Version War. Meanwhile the object was observed in great detail with increasingly potent telescopes, despite the obscuring dust of the Running Chicken Nebula. Several waves of star formation occurred in this nebula over the next few millennia, but for some astronomers the most interesting object was the mysterious disk, now confirmed to be artificial and of xenosophont origin. No alien spacecraft were ever observed near the object, although the curious structures near the poles appeared to be actively self-maintaining.
Occasionally, the idea of sending a long-range exploration mission was raised by those interested in the Rak Mesba, but up to the Central Alliance era no such mission was ever executed. Even using reactionless drive exploration craft this distant star would not be reached until some time after 10000 AT. However the temporal displacement afforded by the expansion of the Wormhole Nexus could allow a craft to effectively travel into the future to a limited extent, as measured using so-called Nexus Time. Eventually, the Terragen Sphere expanded sufficiently that a mission launched from Hutan Baru in the Carina Reach could reach Rak Mesba in the early 9000s. Hutan Baru is a system connected to the Carina Reach (a subsystem of wormholes which has significant temporal displacement). This system is 430 light years from Rak Mesba.
The foremost modosophont expert on Rak Mesba was a Mawas (provolved orangutan) named Jafri Malin Salleh. He appealed to the local Carina archailects for support, and was provided with a fast displacement drive survey ship, the Pertanyaan, piloted by Anggun, a customised transvot entity optimised for exploration and contact. Transvots are virtual robots designed by transapients and archailects, and are often used for difficult and potentially risky missions; although they are as capable as a typical transapient entity, they are not truly sophont.
The ship was launched in 8512 AT. A few hours into the voyage, Salleh and his small survey team entered nanostasis, leaving the ship in the care of the transvot pilot, Anggun. Of course, the transvot pilot was completely capable of fulfilling the mission by itself; but the Carina archailects chose to send Salleh and his team for reasons of their own.
 Image from Steve Bowers | |
| The Running Chicken Nebula as seen in 1322 AT; the alien megastructure known as Rak Mesba is located behind this nebula, as seen from much of the Terragen Sphere | |
Entering the outer reaches of the star system, Salleh and Anggun confirmed that the system holds no other objects apart from thinly distributed dust grains. Salleh suspected that the system had been artificially cleared to reduce the risks of meteoric impact.
Two slowly blinking, diffuse light sources hover above each of the star's poles arranged into rings; these rings consist of several thousand separate solettas. Each soletta consists of four circular mirrors, each with a diameter of just under nine kilometers, separated by equal-sized gaps, slowly spinning beneath a thin square of reflective material measuring slightly more than six kilometers on a side. These structures had been studied at interstellar distances for thousands of years; now Salleh could see that they were held in place by almost-invisible tethers, held in tension by light pressure, a detail which had never been seen before.
As the Pertanyaan came closer, the blue haze of atmosphere resolved into an enormous planetscape, complete with land masses, oceans, and swirling spiral cloud formations. Salleh and Anggun began many hours of trying to communicate with the flattened ring and who or whatever might be inhabiting it. Receiving no replies and hearing nothing but static coming from the giant ring, the ship entered a high parabolic orbit over the megastructure for a closer inspection, though (Salleh hoped) not so close as to worry the disc's inhabitants (if any). The height of the orbit, aside from concerns over the reactions of the disc's residents, was dictated by the fact the Rak Mesba's gravitational field did not obey the inverse-square law, and decreased only slightly at altitudes lower than the outer radius of the megastructure. If no communications were received, Salleh reasoned, the singleship could spiral into a closer orbit. At this point, the plan was to orbit the entirety of the disc to gather a more complete survey of this huge object.
The mass of this disk had previously been estimated at over 1400 solar masses, using the gravitational space-time distortion of background objects; in order to refine this estimate, the orbital path of the Pertanyaan was used to investigate the mass distribution in detail. Such a very massive object would presumably have required the disassembly and transmutation of numerous stars, and would probably have been a very long-term project, and would have been accompanied by a great deal of waste heat. But there are few clues to the date of its construction.
The inner and outer rims of the disc are covered by huge plates composed of a nickel-iron alloy, which serve as a base for a variety of different structures attached to the rims. The four-kilometer-wide strip of nickel-iron plates on the inner rim is almost entirely covered by what appear to be photovoltaic arrays. A longer strip of identical width on the outer rim is studded with clusters of what appear to be huge docking cradles, fuel storage tanks, and cargo-handling equipment, punctuated by unlit cavernous bays open to space. A mixture of rock and regolith fills the interior of the disc.
Using cosmic neutrinos, Saleh and Anggun scanned the disc's interior; this revealed a one-centimeter thick layer of nickel-iron alloy, identical in composition to the plates covering the inner and outer rims, forming a disc at the center of the megastructure and connecting the inner and outer rims. realizing such a structure could not generate the gravitational effects the ship had encountered, Salleh and Anggun deduced that, unlike the metal plates on the exterior, this interior ring must encase something like a very thin sheet of mag-graphene, woven into a very loose mesh. Doppler measurements confirm that numerous elements of this mesh are rotating rapidly around the star, acting like an array of orbital rings within the structure to maintain its shape and position relative to the star.
The vast spaces between Rak Mesba's rims, a total area of more than 268 quadrillion square kilometers (about 525.6 million times the surface area of Earth), are dotted with rivers, lakes, and oceans (many larger than some planets) on both sides of the megastructure; liquid water covers slightly more than twenty-eight percent of the surface. The remaining area is a mixture of terraced plains, grasslands, marshes, deserts, beaches, snow-capped mountain ranges, and even tundra near the outer rims. Sixteen circular "wells," which appear to connect the two sides of the megastructure, are arranged in a logarithmic spiral pattern extending between the rims. Much of the land surface appears to be covered with various sorts of plant-like life, though the onboard spectroscope could not identify what chemicals the organisms would use for photosynthesis if they can do so. Dotted here and there, mainly along the coasts and along riverbanks are what appear to be sprawling cities, connected by traceries of roads and other transportation pathways. Salleh couldn't be sure, but all of them looked as if they had long ago been abandoned. The surface is illuminated every twenty and one-half hours by a combination of light filtering in from the inner rim and light reflected by the solettas. Darkness, or rather a dim twilight, of about the same length follows when the landscape is below a gap between the mirrors.
Above the landscape, low altitude clouds spiral across the skies of Rak Mesba beneath gossamer streaks of wispy clouds whipped along by the disc's high rate of spin (938.5078 kilometers per second) in an atmosphere composed of nitrogen, oxygen, various oxides of nitrogen, carbon dioxide, methane, and numerous trace gases, with an average surface pressure of almost two atmospheres (slightly higher near the inner rim and slightly lower near the outer rim). The dense atmosphere, along with the relatively rapid revolution of Rak Mesba, transports heat throughout each of the disc's two habitable surfaces. The short "year" and even shorter "day" give Rak Mesba an ever-changing weather, as air warmed by YTS 8222-0109319 and the solettas rises in a moisture-laden high-pressure zone that spreads toward the cooler outer rim, finally ending its high altitude journey, after releasing nearly all of its moisture along the way, above the "cold zone" as a low-pressure cold dry air mass that descends to the surface to begin its return to warmer climes in a gigantic Hadley cell. If the disc were stationary, this would be a simple enough pattern of circulation. But the giant habitat revolves fairly rapidly, and as it does both the sunlit "warm zones" and the darkened "cold zones" are in constant motion. As a result of this radial circulation, coupled with the high velocities imparted by the disc's rotation, the upper levels of Rak Mesba's atmosphere are extraordinarily turbulent, though nearer to the surface calmer conditions prevail. The atmosphere is held in place by ninety kilometer high walls made of huge diamondoid sheets that encircle both the inner and outer rims on each side of the megastructure. These walls each measure two kilometers thick at the base and taper to a thickness of only twenty meters at their summit.
Around both the inner and outer circumferences are a total of ninety-six large turret-like structures arranged in three rows, along the tops of the retaining walls and along the midline of each rim, of sixteen structures per row. Although their actual purpose is unknown at this time, it is believed by some researchers that they are a part of the system which maintains YTS 8222-0109319's position at the exact center of the disc's inner radius. Others have voiced the opinion that these "turrets" may be part of an asteroid defense system (though the two functions are not, it can be argued, mutually exclusive). There are also a number of large coil-like structures located at various locations around the tops of all four retaining walls; at the present time, their function is unknown.
As the survey ship was about halfway through its fourth orbit of Rak Mesba, Anggun informed Salleh that they had apparently been fired upon by the disc. At that point, they retreated from the system as rapidly as was safe, and started for home. Inspection of the Pertanyaan revealed significant damage to an aft radiator panel, apparently caused by a high-energy coherent beam of gamma radiation. The damage sustained, however, was not critical, and the survey ship managed to return without further incident. It has been suggested that the vessel may have accidentally been struck by an element of the disk's perturbation control system, though at the present time whether it was accidental cannot be confirmed.
Following the receipt at Hutan Baru of Salleh's initial report in 9513, a great deal of interest in mounting follow-up expeditions to Rak Mesba has been generated, mostly among various corporations and institutes. However, in light of the possibly hostile nature of the artifact and its builders, initial enthusiasm has waned somewhat as considerations of how to defend an expedition from the possibility of attack have entered into preparations for further investigations of Rak Mesba.
When Jafri Malin Salleh returned home on Brahe 8, 9695, he was greeted with great enthusiasm and curiosity from his peers and fellow citizens, and he became something of a local celebrity. His status assured, Salleh has, as of the time of this report, gone on to attract a number of mates as a sign of his social success.
The age of the artifact is unknown, though it appears to be well maintained, as no apparent damage was observed. The nature of its current inhabitants, if any, is similarly unknown; the laser attack could simply have been an automated proximity response. No currently active centres of civilisaton were observed by Salleh and his team. One popular theory is that the entire structure is a single transapient or archailect-level entity; Rak Mesba has sufficient mass to support a S:4 entity or several such beings. Another theory is that the biosphere itself is sentient, or contains many sophont envomes of unknown characteristics.
Nor are there any readily apparent clues as to who built it, when and by what methods, or how long it took to construct. If the builders of Rak Mesba are indeed absent, then their methods and reasons for building the megastructure, and for possibly abandoning it, may never be known.
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Development Notes
Text by Radtech497
Updated by Steve Bowers , June 2025, with ideas from Todd Drashner and Sandcastles
Initially published on 10 December 2010.
Updated by Steve Bowers , June 2025, with ideas from Todd Drashner and Sandcastles
Initially published on 10 December 2010.
